Modulation of CD19 promoter activity in cHL and B-NHL cell lines. (A) Expression of the B-cell–specific surface marker CD20 on B-NHL samples (follicular lymphoma [FL], left; diffuse large B-cell lymphoma [DLBCL], right), but not on cHL samples (with CD30 as a typical cHL marker). Standard hematoxylin and eosin (H.E.) staining to visualize morphology. Note CD20⁻ HRS (arrowheads) surrounded by a few infiltrating, CD20⁺ nonmalignant B cells in the cHL sections. (B) Endogenous CD19 surface antigen expression levels detected by flow cytometry. MFI of individual cHL and B-NHL cell lines (left), and group average of each entity (right). (C) Firefly luciferase-detected CD19 promoter reporter activity, normalized by total protein content in a similar panel of individual (left) and entity-grouped (right) cHL and B-NHL cell lines as in panel B. (D) MFI of CD19 surface antigen expression in cHL and B-NHL cell lines upon 5-Aza/TSA treatment or left untreated (UT) by flow cytometry (individual cell lines, left; average of B-NHL cell lines, right). (E) Firefly luciferase–indicated CD19 promoter activity in cHL and B-NHL cell lines upon 5-Aza/TSA treatment (as in panel D). Data are presented as mean ± SEM. All experiments were done at least in triplicate; *P < .05 throughout the figure.